Detection of histological markers for carcinomas has traditionally involved the staining of cells or cell markers with fluorescent dyes as indicators. However, autofluorescence is a common problem that ultimately limits the diagnostic utility of the results. This proposal attempts to overcome this limitation by the use of a new reporter technology called UPT (Up-Converting Phosphor Technology). This particle-based technology up-converts infrared to visible light which dose not exist in nature. Therefore, no background fluorescence is produced by the specimens being tested. Superior MicroPowders (SMP) teamed with STC Technologies proposes to develop new phosphor powders for use in phosphorescent immunoassays (PIAs). Superior MicroPowders will determine the feasibility of producing up-converter phosphor powders by spray routes to obtain powders with sizes in the range 400- 5nm. The luminescence and other materials characteristics of these powders will be analyzed to determine if they have suitable performance for use in PIAs. Candidate powders that meet these performance criteria will be used for screening in PIAs targeted at prostrate cancer. The availability of brighter phosphor powders with smaller particle size is expected to lead to broader applications including molecular diagnosis of cancer. The utility of up-converter phosphor powders will increase dramatically if they can be used as in situ probes for molecular detection by reducing their particle size below 400 nm. This proposal seeks to address this need by first concentrating their utility in a staining assay for PSA. If successful, future work will focus on the development of more colors of particles and detection of specific molecular markers.